An Organocatalytic Asymmetric Friedel-Crafts Addition/Fluorination Sequence: Construction of Oxindole-Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters
Release Time:2019-03-09 Hits:
Indexed by: Journal Papers
Date of Publication: 2015-11-06
Journal: ORGANIC LETTERS
Included Journals: Scopus、PubMed、SCIE
Volume: 17
Issue: 21
Page Number: 5168-5171
ISSN: 1523-7060
Abstract: A highly efficient and practical one-pot sequential process, consisting of an organocatalytic enantioselective Friedel-Crafts-type addition of 4-nonsubstituted pyrazolones to isatin-derived N-Boc ketimines and a subsequent diastereoselective fluorination of the pyrazolone moiety, is developed. This reaction sequence delivers novel oxindole pyrazolone adducts featuring vicinal tetrasubstituted stereocenters with a 0.5 mol % catalyst loading in high yield with excellent enantio- and diastereocontrol. Notably, chloro, bromo, and thioether functionalities can be readily incorporated, rendering a broad diversity of the product.
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